Date of this Version
Solís A, Kohlmann B. 2022. Dichotomius woodruffi, a new Dichotomius species of the agenor group from Costa Rica and Nicaragua (Coleoptera: Scarabaeidae: Scarabaeinae). Insecta Mundi 0918: 1–12.
We describe a new species of Dichotomius Hope, 1838, from the D. agenor species-group from Costa Rica and Nicaragua: D. woodruffi Solís and Kohlmann, new species (Coleoptera: Scarabaeidae: Scarabaeinae). Based on this discovery, we confirm that Dichotomius enioi Montoya-Molina and Vaz-de-Mello, 2021 and D. agenor (Harold, 1869) are not currently distributed in Costa Rica. Instead, the only species of Dichotomius that are currently distributed in Costa Rica from the D. agenor species-group are D. centralis (Harold, 1869) and D. woodruffi. We discuss the distribution of the Dichotomius agenor species-group in Central America.
In this paper, we intend to better understand the Costa Rican biodiversity by clarifying the taxonomy of the D. agenor species-group. To achieve this goal, we use comparative morphology (external morphology and male genitalia), collection specimens, electronic databases (National Museum of Costa Rica, MNCR; Escuela Agrícola Panamericana, Honduras, EAPZ), and a literature revision. The present taxonomic analysis includes the description of a new species, an illustrated key for species-group identification for all Central America, and a map indicating the distribution of the species-group in Nicaragua, Costa Rica, and Panama.
Montoya-Molina and Vaz-de-Mello (2021) taxonomically reviewed the Dichotomius agenor species-group and considered it part of the subgenus Luederwaldtinia Martínez, 1951. However, Nunes and Vaz-de-Mello (2019) had previously synonymized Luederwaldtinia with Selenocopris Burmeister, 1846. Nunes and Vaz-de-Mello (2019) fused the species-groups of both subgenera into eleven species-groups and three isolated species as part of the subgenus Selenocopris. Nunes and Vaz-de-Mello (2019) diagnosed the subgenus Selenocopris by the following combined characters: clypeal teeth present, strong; lacking clypeo-genal angle; clypeal and genal margin curved; ventral clypeal process bifurcated and female sixth ventrite three to four times larger than the fifth ventrite, not modified medially. Pardo-Díaz et al. (2019) undertook a phylogenetic analysis of the genus Dichotomius and found support for the existence of a D. agenor species-group and considered it also to be a member of the subgenus Selenocopris. We follow here the last two taxonomic suggestions and consider the D. agenor species-group as a member of the subgenus Selenocopris.